Monday, October 24, 2011

I'm building a big wet grinder for shaping steel after heat treating. This is a 18" diameter wheel, 4" wide at about 80 grit. It weighs 70 lbs and can spin at maximum 1400 rpm. To drive it I have an old Craftsman 3/4 HP 1725 RPM motor from table saw. Using the formula rpm*d1/d2: 1725 * 2.5 / 9 gives ~480 RPM.

The stand now has feet, the motor wired and installed and twist link belt driving the pulley. I'm looking for a simple pump for sending a mist of cooling water over the top of the stone. The pulley and motor need a housing to prevent water, dust, tools etc from falling into the moving bits. Don't want any foreign object damage with 70lb stone.

Monday, October 17, 2011

Cut out the rusted area, leaving the rear structure in place for now to fit new sheet metal. The original shapes are duplicated using shrinking and stretching dies, and some hammering. Everything is ground back to clean steel.

New sheet metal butt-welded in after tacking. The structures behind the well were cut out and replaced too, but those are not visible anymore. The seam at the bottom is sealed with seam sealer.

The area is then primed with self-etching lacquer primer, left to cure and coated with a brush on urethane rubber rock guard about 1/4" thick. It's rubbery, but more like plastic so it doesn't hold water like rubber would.
Matching the texture to the original is difficult, and as you can see.

Monday, October 10, 2011

First, they stole my truck. Stealing a man's truck is like kicking his dog. Or stealing his dog.
Now just a few weeks later, they steal my bike (mountain bike, the kind you push with pedals). It stands to reason that.. some things just don't.. they ought not a' done.. anyhow I'm looking for a person on a big downhiller. It's an 18" Giant Reign X2 (grey/blue) with a dual crown Rock Shox 155-200 mm front fork. There aren't many big downhill bikes in Chicago (it's flat, no mountains), so it's not that difficult to spot one.